This invention relates generally to weaving heddles adapted to be arranged upright in pairs on a heddle frame of a weaving machine of the type utilizing weft injection via a water jet.
The system of weft injection renders the weaving heddles constantly wet such that adjacent heddles tend to stick together, especially at the ends arranged in a row in the heddle frame on the bottom heddle support bar. Because the weaving heddles are so light (each heddle weighing between 1 and 2.5 g) in many cases, the cohesive force of the water is sufficient that they easily stick to one another. This sticking effect is enhanced in most cases in that the water is mixed with the sizing material which comes off the warp threads thereby greatly strengthening the sticking effect.
This sticking together of the weaving heddles is not a new problem and certain methods to remedy the problem have been developed. Nevertheless, the problem has been substantially complicated by the introduction of ever sensitive warp yarns. Among such yarns are the so-called micro fiber yarns which have the need to be processed at very low warp tensions. Thus, even a slight sticking together of the weaving heddles causes warp stripes in the fabric which reduces the quality and sellability of such fabric. Known methods which, among others, are closely related to the known solutions for the problems associated with the pulling-in of the warp threads, are clearly inadequate.
The invention is especially adaptable to heddles with a double row of thread eyes located in a plurality of different horizontal planes, as set forth in U.S. Pat. No. 1,545,904. Such heddles is utilized are presently in a similarly or slightly modified form for fabric made of fine yarns. Such a heddle pair designed to accommodate the number of revolutions of today's weaving machines, is shown generally in FIG. 1 of the present drawings. It can therefore be appreciated that, especially in the area of the end loops at the opposing the heddles, the heddles have relatively large surfaces such that when wetted with water and residues of sizing material cause the heddles to stick together.
Swiss patent 407911 discloses the provision of embossments for maintaining adjacent heddles spaced apart. However the embossments define contact points which are rather small and therefore insufficient to effectively prevent the sticking together of the adjacent heddles.
Other known heddles are provided with corrugations for spacing the individual heddles from one another. For example, U.S. Pat. No. 1,246,002 discloses the provision of two lateral projections each in the upper area of the thread eye and the upper end loop of the heddle. U.S. Pat. No. 2,252,184 discloses protrusions on the heddles between the thread eye and the end loop for spacing the heddles apart. Additionally, a spring is provided to maintain the heddles together, i.e., to position the thread eyes of the individual heddles precisely.
U.S. Pat. No. 2,426,456 likewise discloses protrusions between the thread eye and the end loop for spacing the relatively large surfaces in the area of the end loop and the thread eye to prevent rusting. U.S. Pat. No. 3,349,811 discloses an arrangement of protrusions for spacing apart the heddles similarly as in U.S. Pat. No. 2,426,456. However such prior art approaches, despite the provision of corrugations or protrusions, the sticking together of the adjacent heddles persists and cannot be prevented reliably and with certainty in a manner to positively avoid sticking.